The base mac mini is fairly ass-like, and there are only three possible upgrades:
1.) Tony has generously upgraded the RAM to 1GB
2.) The stock low-rev harddrive has been upgraded to an external 7200rpm drive with 8mb of cache
3.) David Robertson has generously offered to perform the CPU overclocking to 1.5Ghz.
Nice. Very nice. Pulled up the mac mini via vnc onto my Gentoo SPARC box at work. This is so going to rock. It is much faster than I expected it to be. Odd though, it's much faster on the Gentoo SPARC box than on the windows box, even at 24-bit color, despite the fact that the windows box is a much faster box with more RAM...